The pathogen, F. oxysporum f.sp. lycopersici (NFCCI 2790)
was recovered from tomato plants showing typical symptoms
of wilt. The roots of wilted tomato plants collected from
farmer’s field were washed separately with tap water to
separate the adhering soil particles and were cut aseptically
into small pieces of two centimetres each (Harley and Weid,
1955). The root pieces were surface sterilized with 0.1 per
cent aqueous solution of NaOCl for one minute and washed
with sterilized distilled water for 5-6 times to remove traces
of NaOCl. Five such sterilized root pieces were transferred
on to 20ml of cooled Czapek´s agar medium in Petri plates
with the help of sterilized forceps. These plates were
incubated at 25±1°C for 5 days. The pathogen was isolated
and its pure culture was maintained on Czapek´s agar slants
for further studies. The pathogen was identified as F.
oxysporum based on its morphological characters. The forma
specialis of this pathogen was identified using pathogenicity
tests.